U.S. Pat. No. 5,205,238 to Boice discloses techniques for applying controlled stress to animals which results in enhanced eating, drinking, mating or similar behavior. Apparatus mounts on a body part of an animal, such as the tail, and contains a mechanism for applying variable stress to the body part and a mechanism for automatically controlling the variation of stress. The apparatus includes an electronic timing circuit, such as a microprocessor, which is capable of automatically controlling the pressure applied to the animal (and the resulting stress) and is programmable to vary the pressure over time. The amount of pressure applied can be programmed to change with time. Such a device will be called herein an ABM device.
U.S. Pat. No. 4,517,563 to DIAMANT discloses an active transponder that is mounted on an object to be identified. The passive transponder is designed to be attached around an animal's neck, or alternatively by a tag fixedly attached onto the side of the ear. An active transponder is located at a fixed location and energy from the active transponder activates the passive transponder to generate a response.
U.S. Pat. No. 4,535,557 to PORCHER discloses a label for the identification of an object, in particular an ear clip for marking cattle. A portable electronic device is used to obtain the information on the label when it is touched by a special glove.
U.S. Pat. Nos. 4,612,877 and 4,718,374 to HAYES disclose an eartag comprising an identification member and an attachment member located in front of an animal's ear. An electronic signal receiving device is mounted near water bowls or the like to identify each animal in a stall from the signal sent by the ear tag.
U.S. Pat. No. 4,617,876 to HAYES discloses an animal identification and control system comprising an identification tag on the animal having a signal sending device for sending a code signal to a signal receiving device near a water bowl or the like. An animal may be automatically weighed while drinking from the water bowl.
U.S. Pat. No. 4,854,328 to POLLACK discloses an animal monitoring system and more particularly relates to a telltale sensing and transmitting device. The receiver is secured to an eartag or the like to provide an audio and/or visual indication of an elevated temperature. The transmitter is inserted in the animal subcutaneously or in a body cavity to sense body temperature.
U.S. Pat. No. 5,028,918 to GILES discloses a transponder used to identify livestock or the like using radio wave transmissions. The transponder can also be used to monitor functions of the animal such as feeding, body temperature and milk production.
U.S. Pat. No. 5,105,763 to POIESZ discloses a method of identifying an animal from a distance by a miniature responder in the form of an injectable capsule implanted subcutaneously and laterally at the front part of the head.
U.S. Pat. No. 5,309,864 to HARMSEN discloses a method and apparatus for feeding animals. A transmitter/receiver on the feeding station generates an electromagnetic interrogation field and receives the unique code from each animal and transmits this identification to a computer which operates the feeding station to deposit additional feed depending on an animal's code.
U.S. Pat. No. 5,320,067 to LEGRAIN discloses an individual animal identification system in a feeding station. A collar on the animal closes a detection circuit in the station to identify the animal.
U.S. Pat. No. 5,322,034 to WILLHAM discloses an electronic livestock record system that stores the individual animal's identification and performance data on a programmable electronic identification and data storage module carried with the animal. A reading and recording device communicates with the module.
U.S. Pat. No. 5,461,807 to JOHNSON discloses an animal eartag that houses a passive electronic transponder for use in the identification of the animal by a low frequency radio wave reading system.
U.S. Pat. No. 5,526,772 to CURKENDALL discloses a method of electronic identification of bovine animals and other species by an implanted electronic transponder in the leg of the animal. Data representative of the animal's identity and characteristics such as temperature, activity, ownership or the like can be monitored and recorded.
The ARRL Antenna Book, 10th edition, copyright 1964 by the American Radio Relay League, Inc. of Newington, Conn., pp. 186-188, contains a discussion of multiband antennas including directly fed antennas and end fed antennas. These are principally directed at operation in a band of frequencies such as those between 3.5 and 30 megahertz.
The Problems:
One problem with the Boice patent, described above, is that it uses a timed response which is predetermined. It would be desirable to apply stimulation to an animal when the animal is actually eating.
In the prior art it is known to use a feeding box in which an animal approaches, breaks a photoelectric beam and its identity is interrogated. Such a system typically uses a single interrogation-response system per box. The cattle have to be trained to walk into the box in order to get food and, if multiple animals are involved, there may be competition for access to the box which creates an unnatural feeding environment. This makes the results of research conducted using such an arrangement suspect. Accordingly, it would be desirable to monitor the feeding habits of animals under natural conditions such as those found in a loose barn environment.
Another problem with the prior art ABM device is that application of pressure to the animal requires energy. Applying stimulation to the animal at times when it is not needed wastes energy and causes depletion of energy for running the ABM unit.
Some prior art techniques utilize RF energy for communicating between an animal and a sensor. RF energy radiates and propagates for long distances and can be a source of interference. In addition, the use of RF is erratic in some environments.
Prior art systems required a long time to detect a change in the eating habits of an animal which might result from a new diet, from medication or from sickness. When monitoring weight gain or loss as often done in the prior art, it often occurred that a sick animal was not detected until after the disease had progressed to the point of untreatability.